Kitkat Original Milk Chocolate Bites were mispacked with Kitkat Peanut Butter Bites at a Nestlé factory in Sofia, Bulgaria.
As the product contains nuts and peanuts it is a possible health risk for anyone with such an allergy.
The affected pouch bags 104g have line code 12311184, batch code 70720457V2 and best before December 2017.
Nestlé said the investigations show it was a small, isolated incident within the one batch.
A batch consists of about one day’s production but the error did not affect the whole batch and only some products made it on sale. They were distributed in the UK to a limited number of customers.
Nestlé said the recall comes as the batch was incorrectly packed and contains Peanut Butter Bites.
"We received a contact from a consumer advising of the issue, we investigated and then took the decision to recall the batch.
"Our priority at the moment is to work through this recall and communicate with customers and consumers. We are carrying out a full investigation and will put measures in place to avoid a similar occurrence.
“Although these packs are labelled with “may contain peanut and nuts” there is a risk to anyone with a nut or peanut allergy who may consume their contents without realising. Although these products are otherwise safe to consume we are making this recall as a precaution. This does not affect any other Kitkat products.”